On-site generation of electricity can be a good way of reducing grid consumption but there are a number of issues common to all technologies when considering installation processes such as the sizing of the generation, suitability for implementation, how and where they are connected into a building's systems and the grid connection requirements which can all be complex and different for every site. This session informs about the main issues to consider when installing all types of on-site generation and provide information on how to effectively deploy it and gain commercial benefit.

1. Energy Managers Association
On Site Generation
Considerations

2. On-site generation
For this presentation, on-site generation is:-
• smaller sized generation generally below 1 MW
• any technology where generation is connected to feed directly into a
buildings systems, as opposed to being directly connected to the
National Grid
• the equipment can be building mounted or standalone near a building
but connected to it
• the equipment may be owned by the building or supplied via a private
wire connection
• the generation output may all be consumed on site or any excess
exported

3. On-site generation sizing
• On-site generation tends to be sized to fit a buildings basic demands such
as its base load, as opposed to installing the largest amount possible
• Imported energy is much more expensive than what you may be paid to
export so high export volumes can impact financial viability

4. 00.00
10.00
20.00
30.00
40.00
50.00
60.00
70.00
80.00 00:00
00:30
01:00
01:30
02:00
02:30
03:00
03:30
04:00
04:30
05:00
05:30
06:00
06:30
07:00
07:30
08:00
08:30
09:00
09:30
10:00
10:30
11:00
11:30
12:00
12:30
13:00
13:30
14:00
14:30
15:00
15:30
16:00
16:30
17:00
17:30
18:00
18:30
19:00
19:30
20:00
20:30
21:00
21:30
22:00
22:30
23:00
23:30
EnergydemandkW
Time of day
Average daily electricity consumption profiles
Average Monday
consumption
Average Tuesday
consumption
Average Wednesday
consumption
Average Thursday
consumption
Average Friday
consumption
Average Saturday
consumption
Average Sunday
consumption
Min consumption
seen

5. 00.00
10.00
20.00
30.00
40.00
50.00
60.00
70.00
EnergydemandkW
Average daily electricity profiles
Average grid
consumption
Average solar
generation
Example of 100kW of solar PV installed

6. Site grid
consumption (kWh)
Potential solar
generation (kWh)
Monthly solar
absorbtion (kWh)
Monthly solar
absorbtion (%)
Export (kWh)
Jan 35,782 1,541 1,541 100 0
Feb 34,216 3,534 3,534 100 0
Mar 34,574 7,432 7,432 99 53
Apr 29,111 10,516 10,516 98 265
May 30,007 13,221 13,221 96 576
Jun 19,819 15,290 15,290 92 1,253
Jul 27,901 15,782 15,782 93 1,258
Aug 29,037 10,850 10,850 97 333
Sep 27,931 8,213 8,213 98 204
Oct 31,711 4,952 4,952 100 1
Nov 33,173 2,613 2,613 100 0
Dec 37,130 1,554 1,554 100 0
370,390 95,500 95,500 96 3,943

7. 00.00
10.00
20.00
30.00
40.00
50.00
60.00
70.00
80.00
90.00
EnergydemandkW
Average daily electricity profiles
Average grid
consumption
Average solar
generation
Example of 250kW of solar PV installed

8. Site grid
consumption (kWh)
Potential solar
generation (kWh)
Monthly solar
absorbtion (kWh)
Monthly solar
absorbtion (%)
Export (kWh)
Jan 35,782 3,853 3,853 99 23
Feb 34,216 8,835 8,835 94 538
Mar 34,574 18,581 18,581 82 4,212
Apr 29,111 26,290 26,290 74 9,396
May 30,007 33,053 33,053 72 13,084
Jun 19,819 38,225 38,225 69 17,542
Jul 27,901 39,456 39,456 67 19,036
Aug 29,037 27,125 27,125 74 9,703
Sep 27,931 20,534 20,534 75 6,924
Oct 31,711 12,380 12,380 87 1,866
Nov 33,173 6,532 6,532 97 235
Dec 37,130 3,886 3,886 100 2
370,390 238,749 238,749 74 82,562

9. On-site generation sizing
• On-site generation tends to be sized to fit a buildings basic demands
such as its base load, as opposed to installing the largest amount
possible
• Remember that imported energy is more expensive than what you
are paid to export so high export volumes can impact viability
• Consider if generation levels and patterns still fit a buildings
requirements out of normal operating hours
• Oversized CHP can lead to excess heat being dumped, destroying
financial viability
• Battery storage could be considered for excess electricity generation
to prevent export. Heat storage could be considered if excess heat is
produced

10. Connecting generation to the grid
• For any grid connected site, generation rated at more than 4kW (16
Amps per phase) has to obtain permission from the local DNO to be
connected, even if all generation is used on site
• This is classed as a G59 connection
• DNO’s review applications for connection based on a network’s
available capacity and it’s ability to cope with local generation
• Local generation can raise system voltages, create imbalance, produce
harmonics, flicker etc.
• You may get approval but on condition that you prevent any export or a
grid upgrade may be required at your cost
• DNO’s usually provide budget prices or full feasibility studies.These
used to be free of charge but this may vary in future along with the type
of connection offered
© EMA

11. Grid connection for generation
• All G59 sites require permanent protection that prevents
generation if the electricity does not conform with statutory
requirements
• A G59 “panel” is usually fitted to the generation equipment or the
site to comply with this requirement
• To commission generation, G59 witness testing is undertaken by
the DNO and is likely to be required for most installations
• Testing may not be required for type tested systems up to 50kW
• Don’t forget the need for metering in your connection, potentially
import and export
© EMA

12. © EMA

14. Building connecting of generation
Generation providers should provide a full solution but what should you
consider?
• How and where will you connect into the buildings infrastructure?
• You need to be able to electrically isolate at both cable ends
• The connection point for electricity and heat and the cabling and
pipework through a building needs to be rated for full output
• Equipment such as inverters may be required and needs to be housed
• Will generation cause problems with any sensitive equipment?
• Consider the effects of rising and varying voltages from generation
and any possible harmonic impacts on site equipment
• Is there existing standby generation on site? Does it need to be
interlocked?
© EMA

15. © EMA

16. © EMA

17. © EMA

18. Financial incentives
• Each kWh consumed on site prevents import from the grid,
avoiding wholesale cost and all use of system charges
• RO now closed to new entrants and FIT’s only available up to
March 2019.They are technology and installation size specific but
once accredited, paid at a fixed, inflation linked rate for 20 years
• Third party funding sources are still available
• Ensure financial returns are calculated using sensible figures,
especially if being quoted by a third party
• Ensure all costs are taken into account as quotes may ignore
equipment or services not provided by the supplier
• Ensure you include maintenance costs as well as those for removal
© EMA

19. CHP finances
• Financing for CHP needs to take account of the cost of electricity
displaced, the current fuel used to generate heat, the fuel that the
CHP will use as well as maintenance
• Delivered costs of electricity are rising faster than most other fuels
so CHP viability may increase
• If the current heat source in a building is not natural gas but
another such as fuel oil, then financial viability should be better
• Ongoing costs of any new fuel needs to be considered. For
example, a biomass CHP may be viable now but what will the price
of wood chip be in 10 years?
© EMA

20. Summary
• Ensure generation fits your buildings demand and profile
• Ensure it can be connected safely and correctly
• Ensure you can get an agreed grid connection
• Review lifetime income streams and costs
• Ensure sensible figures are used in projections including full
installation, tariff, maintenance and disposal costs
© EMA

21. Thank you
MarkTaylor
Taylor Made Energy Solutions Ltd
Mark.taylor@tmenergysolutions.com
07785 313179