EKONOMI SUMBERDAYA AIR Topik 5. Water Valuation:
Irrigation Water
Yusman Syaukat Departemen Ekonomi Sumberdaya & Lingkungan FEM - IPB
Value & Price
Value ≠ Price The value a person assigns to a good is related to his/her preferences. It is a subjective and individual process. Price is market value or value in exchange, which is determined through the interaction between demand and supply in the market. Pricing of water resources is problematic since water market is generally nonexistence
Water Valuation Pearce
(1993): “There is no activity that can be properly called „valuing water‟”. They actually try to assign monetary measures of individual‟s preferences for outcomes of policy proposals or events. For examples: improvement of water supply, quality, or reliability; environmental public good; degradation of water sources
Types of Water Valuation
Water Valuation:
Valuing water as an input in producers‟ good context, such as agriculture and industry Valuing water in municipal uses Valuing water as environmental public goods
Water as an Agricultural Input
Issues of Water Issues
yang harus diperhatikan: Long-run or short-run models? Water as a Variable or a Fixed Input? At-site (place of use) or at-source (at the location where the water is obtained) measure? Private or Social Prices?
Basic Concept Perkiraan nilai ekonomi (benefit) dari suatu producer‟s good yang tak ber-harga (unpriced) – air - dilakukan dengan isolasi kontribusi dari air dari input lain terhadap nilai total output yang dihasilkan Teori Economic Rent Teori yang relevan: Value of Marginal Product (dengan asumsi air sebagai variabel input)
( Py , Px ,W , K ) Py Y ( X ,W , K ) Px X ( Py , Px ,W ) K FOC :
( Py , Px ,W , K )
For Water :
X j
Py Y ( X ,W , K )
( Py , Px ,W , K ) W
X j
Px j 0
Py Y ( X ,W , K ) W
PW 0
Basic Residual Method
Residual (imputation) method merupakan metode deduktif yang umum digunakan untuk memprediksi nilai VMP Pendekatan yang biasa digunakan: 1. 2.
Product Exhaustion Theorem Theory of Economic Rent
1. Wicksteed‟s Product Exhaustion Method Y f ( X M , X H , X K , X L , XW )
Asumsi:
Product Exhaustion Method: PY Y (VMPM . X M ) (VMPH . X H ) (VMPK . X K ) (VMPL . X L ) (VMPW . X W )
Karena: VMPi = Pi Maka:
( PW . X W ) PY Y ( PM . X M ) ( PH . X H ) ( PK . X K ) ( PL . X L )
Sehingga: PY Y ( PM . X M ) ( PH . X H ) ( PK . X K ) ( PL . X L ) PW XW *
Tabel 1. Rata-rata Nilai Air Irigasi menurut Lokasi dan Musim Wilayah
MT I
MT II
MT III
- Hulu - Tengah
554.760 413.832
366.043 245.401
1.388.742 1.024.310
- Hilir
299.957
172.637
738.302
38 28 21
26 17 12
68 50 36
Water Rent (Rp/Ha/MT)
Nilai Air (Rp/m3) - Hulu - Tengah - Hilir
2. Theory of Economic Rent
Assuming producer is a price taker: TR = Y PY Profit Maximization Condition: P = MC TVC – total biaya penggunaan input variabel (a) TR - TVC = sum of rents and quasi-rents Economic Rent = payment made to an input over and above the amount needed to extract any of that input into its present employment Quasi-Rent (QR) = total payment to fixed factors (b) RNW = non-water related rents (b) RW = water related rents = rents that derive from the use of water in production (c) TR= TVC + QR + RW + RNW RW = TR – TVC – QR - RNW
Economic Rent MC
Py ATCo AVCo
ATC
c b
AVC
a
Yo
Change in Net Rent Method
Ketika penggunaan suatu input dirubah, maka akan menyebabkan perubahan pada penggunaan input lainnya. Misal: ketika ketersediaan air meningkat, maka akan membuka peluang bagi petani untuk meningkatkan penggunaan pupuk, pestisida, atau bahkan tenaga kerja. Producer‟s WTP for an increment of an input is the change in net producer income or value of net rent associated with that increment n Net Income (Z):
Z Y Py X j PX j j 1
Suppose, there is an increment of water supply, which causes changes in Net Rent:
Z Z1 Z 0
Change in Net Rent Method (2)
Change in Net Rent: n n Z Y1 Py X j1 PX j Y0 Py X j0 PX j j 1 j 1
Net income per unit of water (∆W): n n Y1 Py X j1 PX j Y0 Py X j0 PX j Z j 1 j 1 W W
∆Z/∆W = change in net rent associated with an increment in water use.
Mathematical Programming Model
Math. Programming dapat digunakan untuk mengukur benefits dari perubahan dalam penggunaan sumberdaya air dalam suatu proses produksi (pertanian atau industri) Output: change in net rents – WTP for an increment or decrement of an unpriced producer‟s input. Objective function: Max f(π,X) Constraint: A‟ X ≤ B B = vector constraint of production inputs, incl. water Parameter πi is usually a measure the marginal net rent to water in activity Xi
Thank you for your attention
