The document discusses solar photovoltaic (PV) systems in the UK. It notes that despite cuts to subsidies, the number of solar installations continues to grow significantly each year. A PV system generates electricity from solar panels using the photoelectric effect and includes panels, an inverter to convert DC to AC current, and other components. The efficiency of a PV system depends on factors like location and weather conditions. Government incentives like feed-in tariffs have increased interest in renewable technologies, though rates have been reduced.

1. Renewables Series:Solar Photovoltaic Systems
From windturbinestosolarpanels,the UK’sinterestinrenewable energysourcesisincreasing and
PV systemsare fast ontheirway to becomingamainstreamsource of electricity.Despite
Governmentchangestolimitthe costof spendingonrenewables,e.g.byreducingsolarsubsidiesfor
homeownersandsmall businessesasof January2016, the numberof solar installations continuesto
grow.Accordingto DECC, 'As of the endof February2016, overall UK solar PV capacity stoodat
9,213 MW across 867,876 installations.Thisisanincrease of 62% (3,526 MW) comparedto February
2015.’
But what is a PV system?
A solarPV or Photovoltaicsystemisasystemwhereby solarpanels (ortiles)are installed togenerate
a useable energysupplyforaresidential propertyorcommercial unit. Despite itsincreasein
popularityamongsthomeowners, PV systems still onlyaccountfora small percentage of the energy
generatedinthe UK today,whichcouldbe due to a numberof factors – the price of purchase and
installation,the pay-backperiod,orevenjustthe upheaval of havinganew systeminstalled.
However,the UKis boundbyan EU directive toproduce 15% of its energyviarenewable sourcesby
2020 so, inrecentyears,Governmenthasintroducedincentive schemessuchasFeed-InTariffsto
increase interestinrenewable technologies –althoughthese tariffshave sincebeensubjecttocuts
(as seeninthe table below).
So how do solar PV systems work?
A residential PV systemproducesenergyviathe photo-electriceffectandcomprisesanumberof
componentsincluding:
 Solar panels(or a ‘PV array’, oftenbuilding-mounted) orsometimestiles
Solarpanelscontaina numberof semi-conductingcells,usuallymade fromsilicon,which
convertsolarenergyfromthe sun intoa flow of electronsand,therefore,anelectriccurrent.
 Solar inverter
An inverterconverts the directcurrent(DC) outputof asolar panel toalternatingcurrent
(AC) whichcan be usedto powerthe property,orcan be sentbackto the grid.
0
5
10
15
20
25
P1
2012
P2
2012
P3
2012
P4
2013
P5
2013
P6
2014
P7
2014
P8
2015
P9
2015
Q1
2016
pence/KWh
Feed-In Tariff (Payment Rates)

2. The efficiencyof aPV systemisdependentona numberof variablesincluding location, panel
orientationand,of course,weatherconditions.Take,forinstance,the heatmapbelow detailingthe
solarpotential of the UK. Asyoucan see,the furthersouthyouare,the higherthe densityof solar
radiation whichmakes fora more efficientPV system.
It isimportantas well tonote that solar panelsworkbestwhenfacingdue southtoensure theyare
exposedtothe lightforthe longestperiodof time.Althoughitisnotessentialforpanelstobe
orientedinthisway(yourroof maynot be orientedassuch),the efficiencyof the systemwill
obviouslysufferif the panelsare frequentlyleftinthe shade (e.g.if yourpropertyissurroundedby
tall treesor buildings. Furthermore,asyoumightexpect,changeable weatherconditionsinthe UK
can make it difficulttopredictthe energyoutputof a PV system;however, ithasbeenarguedthat
the highwindspeedsinthe UK can helptocool downa PV system, thusincreasingitsefficiency.
Figuresand trends
In 2012 itbecame mandatoryfor an EnergyPerformance Certificate (EPC)tobe issued onorbefore
the commissionof aPV installation.Thiscanbe seenbythe dramatic increase inPV systems
recordedin2012 (inthe graph below). A recentstudyof EPCsundertakenbymembersof the NHER
AccreditationScheme showsthat,afteradip in2013, PV installationshave increased inresidential
propertiesand only time willtell if thistrendwill continue into2016.

3. In addition,the graphshowsapeak in 2015 with3.6% of EPCsfor residential properties recording
the presence of a PV system;anincrease thatwas likelydrivenbycontroversial Governmentplansto
cut solarsubsidiesfromJanuary2016. Whenthese cutswere firstproposed,manybelievedthey
would‘kill off’the renewablesmarket, butcurrentfiguressuggestthatthe industryisstill very much
alive.Thiscomesdespitea‘pause’tothe Feed-InTariff Scheme from15th
January – 7th
February
2016. It isimportantto stress,however,that,assolarpanelsare becomingmore popular, PV
systemsare comingdowninprice.For instance, asolarPV systemthatcost £10,000 in 2012 might
onlycost £5,000 today.
To put thisintoperspective,we have puttogetherapaybackmodel showingyouthe paybackperiod
of a standard4kW systeminstalledonasouthfacingroof at a cost of £5,000 (thistakesthe new
Feed-InTariff ratesintoaccount):
As youcan see,the cost of the systemisrecoupedin9 yearsand2 months – afterthis,the money
broughtin bythe Feed-InTariff isyourstokeep andcan go a longwaytowardsyour yearlybill.In
0.00
0.50
1.00
1.50
2.00
2.50
3.00
3.50
4.00
2008 2009 2010 2011 2012 2013 2014 2015 2016
Percentage of NHER EPCs showing a PV system installed

4. thiscase,the netbenefitinpoundsover20yearsis £8,093. Inadditiontothisextraincome, itis
importantto rememberthatrenewable systemslike thisare agreat wayof cuttingyourcarbon
footprint. Infact,overa 20 yearperiod,thisPV systemsaves34 tonnesof carbondioxide.
What are the benefits ofsolar PV?
 Environmentallyfriendly
SolarPV systemsprovide awayof harvestingenergythatisfreelyavailable,without
producingharmful emissions.So,if you’re consciousof savingthe planet,installingsolarPV
isa greatway to cut yourcarbon footprint.
 Save moneyin the longterm
Solarpanelscan be expensive tobuyandinstall;however,once youhave paidoff the initial
set-upcosts,itis possible tomake greatsavingsonyourenergy billsinthe longterm.
 Feed-InTariffs(FITs)
You couldbe eligibletotake part inthe UK government’sFeed-InTariff scheme.The scheme
paysyou forthe electricityyougenerate whetheryouuse ityourself orexportitback to the
national grid.Asof 14th
January2016, a new FIT scheme wasputin place with lowertariffs.
Thiscame as a blowto bothhomeownersandinstallers;however,whilstthe initiative still
exists,anincentiveremains (albeitaless attractive one).
Please clickhere formore informationonFeed-InTariffs,orclickhere tolearnmore aboutsolar PV
systems.