After four years of hard work, we finally started generating in February 2012. Even 18 months later in October 2013, MannPower and Parker were still working to complete the commissioning of important back up systems which had proven troublesome. Through all this Dave Mann and Jonathan Slater at MannPower have been responsive and take ownership for sorting things out. To some extent you are reminded that we are still seem to be in the 'development' stage of the industry, but to those considering such a system, better to be aware of what it can involve...
Even so, we are now ready to say it was worth it...
The good news..
Power generation; We are generating pretty consistently at an annual rate of nearly 70k KWhr of electricity, in line with the targeted levels. At the same time we are generating 70k KWhr of heat from the heat pumps, with a ratio of 3.6 of heat generated to electricity consumed. If anything, the heat being used is less than we anticipated, given our previous gas bills etc... It probably reflects the additional insulation measures we took and that we hadn't allowed for the efficiency loss of the the gas boiler ie the previous heat input to the house would have been less than the gas consumed and billed. FIT tariff payments; We are now receiving a quarterly cheque from the FIT tariff payments, organised through MannPower (although it did take over 12 months for the relevant authorities to process it!). The FIT Generation Payment on all electricity produced is currently 22.58p per Kwhr. In addition we are paid 3.3p for each unit exported into the grid. We operate under a scheme, at the discretion of the electricity companies, whereby in the absence of additional metering systems we are 'deemed' to export 75% of our output. When combined with the savings in our previous utility bills we are making a start on the 10+ year payback for the scheme Renewable heat incentive; After several delays the RHI domestic scheme was launched in 2014 but allowed for retrospective application within certain time limits. We have ended up qualifying for the 'Non-domestic scheme' on account of the system supplying what are deemed as 3 by our local council for Council Tax purposes. The application process was another major task, but worth it in the end. In combination with FIT it provides a strong financial support for the logic of a combined hydro/electric and heat pump system
Finally there is still the novel pleasure of realising that all light, hot water and heating is coming from the power of the river!