Energy systems are changing. In particular, the previously dominant role of large central power stations, usually sited according to the availability of fuel supplies or cooling water rather than close to the loads they supply, is diminishing. Today’s developed-world energy systems now also rely on a range of smaller-scale, often cleaner and more efficient, decentralized generation units supplying energy to a host building, industrial site or locality. The new name of our magazine reflects this change.
Most large coal-fired power stations were originally sited close to coal mines, and nuclear plants close to rivers or the sea for cooling purposes, and both sent power to consumers over long-distance transmission lines. However, much power and heat is now generated locally.
This magazine has long championed highly-efficient cogeneration and other ‘on-site’ plants, but the decentralized energy sector is much more wide-ranging than these. Alongside decentralized generation plants – cogen and trigeneration schemes, district energy systems, solar photovoltaic (PV) plants and other renewable energy schemes that deliver their output to a host building or organization – there has been an explosion in the development of microgrid power distribution systems, new heat (and cooling) networks, energy storage technologies and demand response initiatives.
These technologies, together with new contractual and commercial arrangements made possible by decentralization, add up to a fundamentally new system for consumers.
No longer does electricity travel in one direction, from central power stations to consumers; rather, local generators now feed power to their own homes, business and industrial processes, and sometimes into power distribution systems. Businesses may switch from being net power consumers to net generators, according to power prices and time of day.
No longer do consumers have to buy electricity which has been generated in old power stations with efficiencies of less than 50% and then subject to significant transmission losses as well. A range of locally-based solutions is becoming ever more mainstream.
It’s perhaps unlikely that developed-world countries will ever abandon established centralized power generation and transmission systems altogether, but there’s no doubt of the increasingly large role played by decentralized technologies. Working with the more traditional centralized plant, decentralized energy delivers security-of-supply benefits. Why not generate at least part of your own energy on-site, with some PV panels, a packaged cogeneration scheme or a connection to the local district energy scheme – and cut your carbon footprint at the same time?
Indeed, while the most outwardly visible change to energy systems over the last couple of decades (and the life of this magazine) has been the strong growth of renewables for decarbonization reasons, the move towards decentralized generation and a more consumer-centric approach has been just as fundamental. And this will only continue.
Moving on – heat, of course, tends not to travel well and so is always local. Engineering ingenuity continues to find new sources of ‘waste’ heat that can be put to use. So far this year I’ve learned of excess heat generated at a data centre in southern Finland being transferred to preheat water for the city’s district heating system. Meanwhile, heat contained in sewage in a wastewater treatment centre in Scotland is being recovered to supply to the local college. And in London, a project to recover heat from the underground railway transport system for use locally is expected to go live this year.
Steve Hodgson, Contributing Editor