Analysis A new report on possibilities for deployment of low-carbon microgeneration machinery in British homes was published yesterday, and has scored big ink. But most of the coverage has ignored the three main messages of the report.
These are fairly simple. Firstly, according to the report, microgeneration in the UK is going absolutely nowhere without massive government backing - in the form of multibillion-pound subsidies, or regulations which would in effect place multibillion-pound levies on homeowners. Secondly, the report's authors conclude that with such massive backing microgeneration might reduce the UK's carbon emissions by as much as a few per cent; though in most scenarios the saving would be less than 1 per cent.
Finally and most importantly, however, the report notes that any success in delivery of lower-carbon national grid electricity would render most forms of microgeneration pointless. Given a halving of the carbon burden of grid 'leccy, widespread takeup of home power machinery would no longer reduce the UK's carbon emissions but actually increase them. (It's important to note that headline-worthy but marginally useful microgen kit such as rooftop wind turbines and solar cells formed only a small part of the calculations.)
The document in question is called The Growth Potential for Microgeneration in England, Wales and Scotland, and it can be downloaded in full here (big pdf). It was produced by consulting engineers Element Energy and was paid for by UK national and local government, the Micropower Council, several power companies, the Energy Saving Trust and the Renewable Energy Foundation.
It won't pay unless we all pay
The report's authors, having done their economic projections into the future, don't see any serious takeup of microgeneration without heavy government backing - to the tune of billions each year.
Subsidy schemes which achieve a widespread penetration of microgeneration have cumulative subsidy costs in the tens of billions by 2030 ... expectations of technology cost reductions appear necessary but insufficient to promote substantial consumer uptake of microgeneration. In the absence of changes to the fundamental energy economics, microgeneration technologies will require a supportive policy framework ... Even with relatively optimistic cost reduction projections up to 2050, microgeneration technologies will struggle to compete for consumers without policy support.
In particular, the most pure and righteous green home power technologies - rooftop wind turbines and solar-electric panels - require huge subsidies, several times the consumer price of electricity, to make them worth installing. Even then, most home users need loans to afford them; and the loans must be cheap or the revenue from selling high-priced subsidised power to the grid still won't cover the payments. Home windmills and solar-cell panels didn't produce enough power to seriously affect carbon emissions in any of the scenarios modelled. But there are many other kinds of microgen equipment, and it was these which seemed likeliest to be successful.
Keeping the home fires burning
Especially attractive in some scenarios are Combined Heat and Power (CHP) installations. Many Brits nowadays heat their homes and water using gas boilers, wasting a good deal of the energy they buy even with the most modern kit. Gas CHP plants cost a lot more than a combi boiler, but generate 'leccy as well as heat; wasting less overall, and so saving money over time. In future, CHP plants might use fuel cells rather than relatively ordinary options such as gas motor or Stirling-engine powered generators.
Making "cautious" assumptions about fuel-cell CHP - which isn't yet available for home use - the report's authors thought it could be brought down to the same kind of price as a combi boiler by using a within-the-realms-of-possibility subsidy regime. This meant that CHP, and particularly fuel-cell CHP, tended to dominate the future microgen projections. Like windmills or solar cells, CHP plants would sell electricity back to the grid if it wasn't immediately required. The difference is that CHP generates a lot more power.
Another crafty option for the parsimonious home owner is heat pumps, which work just like a fridge. Instead of making their insides cold and dumping heat into the kitchen, however, they make the air outside a house (or the ground beneath it) colder, and dump the heat into your radiators or your hot water system. The electricity required to drive the heat pumps is potentially much cheaper than a normal heating bill; but, again, the upfront costs are so large as to discourage most people.