Enter the ‘energy prosumer’

As the cost of solar falls and the technology improves, more homes are generating their own power, says Phil Hart. But can this be done efficiently on a large enough scale to change the energy model?

We’re all prosumers now. We don’t just sit back and consume music, film or news, we’re actively making our own media and sharing it with the world. New technology means more individual freedoms, more creativity – but when it comes to energy it’s a mindset that potentially threatens the historical stability of the industry.

Ten years ago we were still comfortable living with the long-established state of affairs in which very large power stations were delivering stable, consistent power to homes and industry. It looked monolithic, a hard-wired, one-way energy system that psychologically we could always rely on.

With the advent of validated carbon emission concerns and their cure – renewables – that comfortable energy security blanket is being removed. We are moving inexorably toward uncertainty, towards a phase of very significant market disruption. And it’s the democratised nature of intermittent, non-guaranteed renewables and the renewables market that are the source.

New models

The initial success and potential of solar-powered homes has opened the door to whole new models for the energy market. Photovoltaic solar cells are cheap and getting cheaper by the day. The technology is also getting better, with the potential for higher power generation and also better systems for localised storage and more efficient use of what’s generated. About 12 x 1m panels is enough to supply an “average” home’s electricity needs, so as costs plummet it becomes more compelling for homes to be aiming towards self-sufficiency and ­potentially excess sales. Enter the “energy prosumer”, and a steady rise in the number of personal sellers of excess capacity from their own micro power stations. These are individual householders as well as collectives, on estates, in whole villages and towns, with the ability to sell their leftover power to the grid.

There’s nothing fundamentally preventing any organisation or enterprise from generating energy from solar, or from wind turbines, and selling it to the highest ­bidders – and in competition with the traditional major generators – if the commercial structures are in place.

The quandary

So there is a quandary: what is the business model for the future? We need consistency in supply but are building variability through renewables, which is undermining the ability to build that consistency. We need to bring about a change in energy mix as a basis for supporting the ongoing success of solid, large-scale energy enterprises. A way has to be found to guarantee supply of baseload on demand, while limiting CO2 emissions as good custodians of the climate. Making traditional thermal energy plants more efficient must be part of our continuing energy provision mix, giving those in the research field enough time to develop replacement technologies that allow their future retirement without adding impractical risk or cost. Gas is, of course, still a significant polluter, but it represents a good step in the right direction.

The answers

We must improve carbon capture and use technologies to mitigate the remaining impact, and make materials and process improvements to allow more efficient operation. Power storage of various types may be the long-term answer, but we have a long way to go to reach that nirvana. Certainly lithium-based batteries are making great strides and costs are falling rapidly. However, storage capability of this type and size is measured in low numbers of stored hours. Typically in the US, for example, more recent solar plant is being quoted with 20MW x 4hr storage. This is an impressive increase in capability from, say, five years ago and a contributor perhaps to short-term peak demand, but certainly not to inter-day/inter-seasonal power variations. Larger, long-term storage will be a key enabler to the renewables transition for sure, but the technology used to crack that particular problem remains somewhat elusive.

Much current research tends to be focused on looking at ways to make individual systems more efficient. That’s useful, but what matters in the end is system costs, how the total solution can be made to add up commercially. This is what I see as the particular role for Cranfield University, advancing the technical approaches but always with business in mind.

We need to find a way to the total solution, a concerted activity and co-operation to find the tech that works as a system, makes money and supports continued investment. Such a system will contain flexibility and space for the prosumer, utility and other enterprise models and also combines all the critical qualities of ongoing security, future stability, and healthy profitability.