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A fast track to African power

A more sustainable approch, compromising renewables and a backup gas engine-based system, could help ease the chronic electricity shortage that holds back Africa's global competitiveness and condemns many of its people to poverty, argues Dr Jacob Klimstra.

Acomparision among different global regions of their electricity use and economic development reveals how strongly the two factors are related. Figure 1 gives the gross domestic product (GDP) in purchasing power parity (PPP) per person per year as a function of per capita electricity use for the major areas of the world. The correlation coefficient for the red linear trend line has the high value of 0.95. The slight deviations from this trend line can be explained by, for example, the energy wastefulness in the USA and in the oil states of the Middle East on the one hand, and the more frugal attitude in Europe on the other.

Figure 1
Figure 1: The relationship between electricity use and GDP in global regions

In economically developed nations, about one third of total electricity use is end consumption in households, while two thirds of supply is used by industry and services in wealth creation. The use of electricity drastically increases the productivity per person. As Africa scores lowest in both electricity use per capita, as well as in GDP per capita, it needs substantially more electric energy to become globally competitive and abolish poverty.

Electricity consumption per person per year in Africa averages about 500 kWh – only 20 per cent of the world average of 2500 kWh. Yet even this low figure far overstates consumption by the vast majority of Africans. If electricity use in North Africa and the Republic of South Africa is excluded, annual per capita consumption for East, Central and West Africa is revealed as only 180 kWh. This means that about 80 per cent of Africa's people use less than 7 per cent of the world average – or only 1.5 per cent of what the average North American citizen consumes. Much of Africa's population is not even connected to a grid.

A few things are obvious, such as:

  • Africa's overall consumption is not representative of the continent. Electricity use per capita in the countries in the North of Africa, as well as in the Republic of South Africa is much higher than in most African countries.
  • Raising productivity and living standards across Africa to a global competitive level requires at least a five-fold increase in average per-capita electricity supply.
  • For the bulk of Africa's population, at least a ten to 20-fold increase in average power supply is needed to provide reasonable living conditions and economic competitiveness with the rest of the world.

It should be noted that for a more comfortable life in homes and communities, a residential electricity supply of 500 kWh per person per year might suffice. However, much more electricity is needed to boost economic productivity. Treating and refrigerating valuable agricultural products, powering mining activities, manufacturing goods, handling data and providing communications all require considerable amounts of electricity.

In Ethiopia, for example, electricity supply is growing fast, by about 7 per cent per year, which is already quite an achievement. But to achieve economic competitiveness, average electricity use per capita should rise from the current 50 kWh per year – one of the world's lowest figures – to at least a modest 1000 kWh. If this were done in, say, 15 years, the annual increase would be about 22 per cent. But even at such a high growth rate, Ethiopia's per-capita power supply will still end up less than a third of the global average, as many scenarios indicate that global electricity use will have doubled in 20 years' time.

So how can Ethiopia rapidly produce more electricity and distribute it to its population? The country needs capital for investments as well as enough primary energy for its power plants. And EEPCO, the national electricity company, has prepared plans that are fully in line with this analysis. The country is increasing electricity exports to its neighbours – Kenya, Djibouti, Sudan and South Sudan – to generate income for further investments in the power sector. Loans from the World Bank and the African Development Bank of $1.3 billion are being used to substantially increase hydro capacity – through projects such as the 6000 MW Blue Nile and 1870 MW Gibe III plants – as well as wind farms and geothermal generators.

Ethiopia has Africa's greatest hydropower potential and plans to add 37 GW of renewable capacity over 25 years. Providing 85 million inhabitants with 1000 kWh of electricity per year requires 20 GW of capacity running at a capacity factor of 50 per cent. Extra capacity can be used as a sustainable source of money from electricity exports.

EEPCO's plans are exactly what the country needs. However, plans are always accompanied by complications:

  • Ethiopia's population is growing at 3 per cent per year, which accelerates demand;
  • A loan of $1.3 billion for 8 GW capacity already totals 4 per cent of Ethiopian GDP;
  • High dependence on hydro raises risks from fluctuating annual rainfall.

Nevertheless, the planned increase in power production is crucial for lifting its economy to a competitive and sustainable level. With an economic hydropower potential of 160 TWh per year, an annual electricity production of 2000 kWh per capita is possible. If 1000 kWh per capita is enough in a sustainable society with a good climate, the country can export 80 TWh per year. For an electricity export price of $0.10/kWh, that yields $8 billion per year. In the long run, this offers great expectations for Ethiopia.

Electric energy resources

Many African countries lack Ethiopia's abundance of renewable natural resources, such as hydro, and therefore still depend heavily on fossil fuels for electricity generation. For all of Africa, 40 per cent of electricity is produced from coal, 30 per cent from natural gas, 15 per cent from hydro and 12 per cent by oil, estimates the International Energy Agency. The contribution of biofuels, wind and solar based energy to electricity production is negligible at best.

Figure 2 reveals how the Republic of South Africa hosts almost all of the continent's coal applications, while North Africa generates its electricity primarily with gas and oil. Excluding South Africa and North Africa, hydropower then becomes the dominant electricity source for the rest of Africa's 780 million people. However, much hydropower is based on run of the river systems in which output fluctuates highly with rainfall.

Figure 2
Figure 2: Africa's regions show large differences in which primary energies are used in power production

For most African countries other solutions must be found to increase electricity production. A relatively simple solution could be to build a transmission and distribution (T&D) system for natural gas throughout Africa and to use gas from the large reserves found in Nigeria and North Africa to fuel power plants. But most African countries cannot yet afford to pay as much for gas as Europe and Asia, so the gas does not go to East, Central and West Africa. Africa's huge coal resources present another option, but one that conflicts with aspirations to reduce global carbon dioxide emissions.

Nigeria is favourably placed to generate electricity to supply its economy with natural gas. At the moment, the country's annual per-capita GDP (PPP) of $1190 and annual per-capita electricity use of 120 kWh are in the same low range as countries such as Ethiopia. Exploiting Nigeria's 7 trillion m3 conventional gas reserves over 50 years means that 140 billion m3 can be used each year. This situation can be compared with that in the Netherlands, where a gas field of about 2.8 trillion m3 has been producing between 60 and 90 bilion m3 per year over 35 years. About half of that was exported by pipelines to neighbouring countries.

If Nigeria used 50 billion m3 gas per year for electricity production, it would yield some 250 TWh per year, or 1600 kWh per capita per year. That would transform its economy and living standards. Remaining potential gas production, some 90 billion m3 per year, could be used for exports. The country already exports 25 billion m3 per year as liquefied natural gas. Nigeria's unconventional gas resources are estimated to total in the region of 7 trillion m3.

Outside Nigeria and North Afirica, Africa's natural gas reserves are limited, although South Africa appears to hold promising resources of unconventional gas, such as shale gas and coal-bed methane. Countries such as Angola, Cameroon, Mozambique and Namibia do however have sizeable gas reserves, as shown in Figure 3, which could be used intelligently to enhance electricity production. But burning that gas in large baseload power stations would be unwise. The technical life of a large power station is at least 30 years. Namibia's 100 billion m3 of natural gas, for instance, could fuel a 2000 MW baseload power plant for 30 years, but then all the gas would be gone.

Figure 3
Figure 3: Sub-Saharan natural gas reserves, excluding Nigeria (billion m3)

It would be much more advisable to use the gas with flexible power stations, such as engine-based, systems as a long-term backup battery for intermittent renewable energy sources. In the more distant future, say around the year 2050, a large proportion of renewable electricity sources will dominate power production. One can already notice early developments of this in Germany and Denmark. Africa will not be an exception. The costs of solar photovoltaic (PV) panels are rapidly decreasing and the African continent is rich in sunshine.

Taking a strategic view

Africa has a great potential for renewable energy, especially for solar PV systems, hydroelectricity and geothermal power sources. Sadly, it is the chicken-and-egg syndrome that hampers a quick implementation: the continent cannot earn the capital required for power production equipment because of its low productivity, which results from a lack of electric energy. Therefore, it is essential that as much external support as possible for the continent must be directed towards providing the economy with electric power. In addition, a significant proportion of the proceeds from the African boom in selling minerals to the rest of the world should be used for enhancing electric power production.

Investing in power plants in Africa can even be quite lucrative. Considerable suppressed demand for electricity means that newly built power capacity will quickly find customers. Many potential customers use small generators fuelled by petrol or diesel oil, which provide less economic electricity than efficient power plants. Household members that spend hours per day in finding fuel for cooking would be more than happy to use efficient electric cookers.

In defining a proper strategy for a rapid electrification of Africa, one has to take into account some characteristic boundary conditions:

1. The existing low density of electricity use;

2. Limited T&D networks;

3. Low availability of local capital;

4. A preference for using local manpower to enhance employment;

5. A preference for local maintenance and repairs;

6. A lack of substantial natural gas reserves outside North Africa and Nigeria;

7. Potential for natural gas as backup reserves in several countries;

8. Large potential for hydropower in some countries; and

9. Large potential for geothermal power and solar PV in many countries.

Approaching the challenge should involve the following elements:

1. Installing quality generating equipment with a relatively low price (such as gas fired modular generating units);

2. Installing generating equipment that can compensate for intermittent renewables;

3. Creating political stability for long-term power purchase agreements;

4. Avoiding excessive red tape;

5. Avoiding excessively stringent emission regulations that would be designed for a metropolis in the developed world;

6. Providing excellent reliability with multiple units in parallel; and

7. Avoiding the trap of installing single large generating units.

Solution to Africa's power shortfall

While investment costs have deterred Africa from implementing solar PV – which currently provides only 0.004 per cent of its electricity – its costs will soon be competitive. Batteries to cover demand when the sun fails to shine remain prohibitively expensive, although affordable batteries are expected to be developed over the next 20 years.

As a medium-term solution, new flexible engine-based power stations running on natural gas, or even heavy fuel oil, should therefore be installed to cope with variable demand and compensate for variations in output from renewable energy sources.

In Africa, backup systems will be needed for a few hours after sunset and during periods of low rainfall. The backup systems will need to have a very high ramp rate to cope with the rapid decline in solar PV output just before sunset (see Figure 4, based on a gas engine-based backup system). But backup power plants in the future will have to run for far fewer hours per year than traditional power plants (see Figure 5). Plants run on coal and especially nuclear remain expensive to run for limited hours and are unsuited to frequent starts and stops. On the other hand, relatively low-investment costs for gas and oil fuelled engine-based power plants result in low capital costs per kWh when running limited hours.

Figure 4
Figure 4: High ramp rates needed for backup generators for PV at sunset
Figure 5
Figure 5: Demonstrating the effect of a reduced utilisation factor on capital costs per kWh

Furthermore, when power demand varies greatly, generating systems with multiple units in parallel offer many advantages. Individual units can be switched off when their output is not needed instead of running at low load with low efficiency and high specific maintenance costs (see Figure 6).

Figure 6
Figure 6: The high overall fuel efficiency of a cascading power plant

Today's modern economies depend heavily on a reliable power supply – blackouts and brownouts hamper productivity and reduce product quality. Using the multiple generating units concept for power plants with an n+2 approach provides reliability of power supply. This is especially the case in Africa, where transmission grids are often weak or even lacking. This high reliability can never be achieved with single big power plants. A reliability of 99 per cent/generating unit is a practical technical standard for an individual generating unit.

A system with six generators in parallel where five are able to carry the load (n+1) is already able to create an electricity supply reliability of 99.85 per cent. One extra unit (n+2) can serve as reserve capacity when one of the others is undergoing maintenance. In the case of just a few large generators supplying to the grid, the tripping of one unit will have a significant impact on the grid and can easily cause a blackout.

The principle of power plants with multiple units in parallel can be very advantageous in countries such as Nigeria where a widespread gas-based power generating system needs great flexibility, especialy in the beginning. Gradual increases in power demand can be easily met by installing extra identical engine-based generating units.

Even in Nigeria, considerable solar PV is expected to be installed resulting in high ramping rates for fuel based generating equipment just before sunset. Such an approach might preserve much of the precious hydrocarbon resource as feedstock that can act as a battery for the future. Having ample access to electricity will lift the country permanently out of poverty.

Conclusion

Removing poverty, famine, instability and conflicts in Africa requires a substantial increase in electricity generation in the continent. The current average per-capita consumption of 180 kWh per year in East, Central and West Africa has to be raised rapidly to at least 1000 kWh, with a further expansion in the longer term to 2500 kWh.

Ultimately, power production has to be based on sustainable resources, as in the rest of the world. However, to pull Africa out of the vicious circle of uncompetitiveness caused by a lack of electric power, a smart system based on flexible engine-based power plants running on fuels, such as natural gas is needed. Such a generating system quickly provides the population with the power it needs and can eventually serve as a backup system for developed renewable energy resources.

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