Developing a lower carbon estate – the Greenhouse project in Leeds

It is good to see that a new development has started in Leeds which will use many types of renewable energy. The development, going under the name of “Greenhouse” will comprise some 170 flats as well as offices in South Leeds, when it has been finished. Although the developers claim that the project will be “carbon neutral” in that it is expected to generate more energy from renewable means than the inhabitants will consume, there is some doubt in my mind whether this will actually be the case.

Clearly the buildings will be built to be intensely energy efficient. They will have high insulation, which will mean that the heat load required will be very small. Water heating will come from solar panels, and space heating and air conditioning from ground source heat pumps. Although the solar panels will operate with very small amounts of electricity, all of which can be harnessed from photovoltaics (although it does not seem to be the case at greenhouse) heat pumps need electricity to create and exploit the heat differential between underground and surface temperatures.

Heat pumps operate at a range of coefficient of performances. In mild weather a heat pump will produce around 3.5 times the energy that would normally be used if you were to rely on electricity alone. If you generate electricity from coal, then the carbon dioxide emissions of using a heat pump are just a little less those of than using natural gas for heating. In cold weather the heat pump’s “COP” falls to about 2.

The project has roof mounted wind turbines. These will generate small amounts of electricity – not enough as far as I can calculate to supply the development, because the turbine blades appear to be too small for this, as far as I can tell from the information that I have available.

The specification of the flats that can be purchased includes “A” rated energy efficient appliances and smart switches.

Now even though this development will not, I expect be carbon neutral, let alone energy positive as the developers claim, it is nevertheless one of the few examples of development in the United Kingdom where the developers are combining usefully all feasible means of renewable energy generation and renewable energy support.

It shows what can be done now, today, without having curious concepts of Zero Carbon Homes and the developers should be congratulated on their efforts to reduce carbon dioxide emissions from those who will live in their development.

There is no reason why all homes today could not be built using solar panels, photovoltaics, and with larger wind turbines on site, as well as using ground source heat pumps if the carbon cost is lower than using natural gas. The Greenhouse in Leeds is an example of the way forward; they had to get public funding to install the renewable energy systems.

The Government will create some complex rules about “Zero Carbon Homes” when they discover, by consultation, what a Zero Carbon Home is, and are also adding to the building regulations (but not enforcing them) so that the changes in building take place by a series of steps.

I fear that this approach will fail the environment. We need simple regulations now – perhaps one mandating two forms of renewable energy on all new construction now, so that we can take advantages of the carbon reductions that devices like solar panels can deliver today. There is no point in reinventing the wheel – the wheel we have already works perfectly adequately.

Finally although I have criticised some of the hype about Greenhouse in Leeds, I should praise them for their bold innovation. You can check out the development at